1. Field of the Invention
The present invention releates to munition systems in which control of the detonation process is critical and in which weapon detonation must occur only at desired times with an extremely high degree of reliability. More specifically the present invention relates to an electronic arming and firing device which meets or exceeds the safety criteria established for "out-of-line" fuze systems.
2. Description of the Prior Art
An "out-of-line" explosive train is one in which the primary explosives are physically separated from the output lead and booster explosives to prevent the detonation of a warhead or other main explosive charge until after the arming process has occurred. Separation of explosive train components in "out-of-line" systems is accomplished by interposing a physical barrier between explosive train components or by maintaining explosive train components physically misaligned so as to be uncommunicative until after the arming process is completed. When the arming process is complete explosive train components are "in-line" and initiation of any explosive train component will result in detonation of the main charge. Theoretically and preferably explosive train components are initiated in a predetermined sequence after arming has occurred.
"Out-of-line fuzing" is the currently accepted method of munition fuzing to the virtual exclusion of use of "in-line" fuze systems. The use of "out-of-line" fuzing schemes has been mandated by safety considerations which are traceable primarily to what was heretofore the necessity of using a sensitive detonator to initiate the explosive train. The necessity of using a relatively sensitive detonator dictated the physical separation of explosive train components to ensure that accidental initiation of the detonator would not ultimately lead to an untimely munition detonation.
Current art "out-of-line" fuzes are essentially mechanical in nature although some fuzes utilize electronics to accomplish certain timing functions. Present fuze systems utilize electronic or mechanical timers to control movement of the explosive train from an "out-of-line" to an "in-line" condition.
While current "out-of-line" fuzes have proven effective, it has been determined that there is a need to improve overall fuze system reliability. Particularly, advances in the electronics art and in the design of less sensitive warhead initiators have focused attention on the advantages of "in-line" fuzing over "out-of-line" fuze systems. These advantages are not insignificant. First, current "out-of-line" devices are more prone to breakdown of a mechanical nature than current electronic devices are prone to electronic malfunction and the reliability of electronic components has become an accepted fact.
Second, current devices which utilize mechanical, electromechanical and pyrotechnic components are becoming increasingly costly while the cost of electronic components has steadily fallen. Further, much of the mechanical fuze technology and manufacturing capability, which has historically been intertwined with mechanical watch movement technology and production is disappearing, making certain critical mechanical components difficult and expensive to procure.
Third, current fuzes which do utilize electronics are capable of being improved upon in several areas. One particular area requiring improvement is in the area of the power and logic interface between a munition and the platform which carries and releases it. Interface disruption has been known to occur during the munition release process resulting in improper logic and/or power transfer to the munition and the faulty functioning or nonfunctioning of the munition fuze.
Fourth, many current fuze designs utilize "one-shot" or single event pyrotechnic components in the arming sequence. The use of such components whether in the arming device itself or elsewhere in the fuze results in the inability to nondestructively test the fuze system. A necessarily less reliable fuze results when compared to a device capable of being nondestructively tested.
Finally, the arming process of many current fuze systems relies at some point on stored energy. The use of stored energy in any phase of the arming process is to be avoided if possible in that its inadvertent release necessarily results in a less safe and likely a dudded munition.
Before the development of the device of the present invention there had not been any electronic arming and firing device with the safety and reliability necessary for the acceptance of use of an "in-line" fuzing system.